JP6398718B2 - Conductive paste, conductive pattern manufacturing method, and touch panel - Google Patents

Description

  The present invention relates to a conductive paste, a method for manufacturing a conductive pattern, and a touch panel.

  In recent years, mobile electronic devices such as smartphones and tablet PCs have been actively developed. Miniaturization and high definition are required for displays and touch panels, which are one of the members.

  A vapor deposition method is known as a method for forming a conductive pattern on a substrate such as a display or a touch panel. The vapor deposition method can form a high-definition pattern of 20 μm or less. However, cost increases due to capital investment and complicated manufacturing processes are problematic.

  In order to form a conductive pattern at a lower cost, a material for forming an organic-inorganic composite conductive pattern including a resin as an organic component and a conductive filler as an inorganic component has been put into practical use. That is, a so-called polymer-type conductive paste in which a large amount of silver powder, copper powder, or carbon powder is mixed as a conductive filler with a resin or an adhesive containing a resin has been put into practical use.

  Many of these conductive pastes can obtain a conductive pattern by heating and curing a pattern formed by a screen printing method (Patent Documents 1 and 2). However, it is difficult to accurately form a conductive pattern of 100 μm or less.

  Therefore, conductive paste capable of acid etching (Patent Document 3) and photosensitive curable conductive paste have been developed (Patent Documents 4 to 6).

JP 2012-18783 A JP 2007-207567 A Japanese Patent Laid-Open No. 10-64333 JP 2004-361352 A International Publication No. 2004/61006 JP 2013-101861 A

  However, for the conductive paste capable of acid etching described in Patent Document 3, it is necessary to form a resist layer when forming the conductive pattern. Therefore, there is a problem that the manufacturing process is complicated.

  In addition, in the conventional photosensitive curable conductive pastes described in Patent Documents 4 to 6, there is a problem that the obtained conductive pattern has low conductivity, the brittleness of the obtained conductive pattern, or insufficient adhesion to a substrate or the like. It had been.

  Further, there has been an increasing demand for using a substrate made of a polymer. Since a substrate made of a polymer is inferior in heat resistance, there has been a demand for conductivity expression under curing conditions in a lower temperature range.

  In view of the above, an object of the present invention is to provide a conductive paste that has a remarkably high adhesion and is capable of forming a fine conductive pattern that exhibits conductivity under relatively low-temperature curing conditions.

In order to solve the above problems, the present invention provides a method for producing a conductive paste and a conductive pattern, and a touch panel described in the following (1) to ( 6 ).
(1) Compound (E) and / or carbon containing conductive filler (A), zwitterionic compound (B) , thermosetting compound (C) and photopolymerization initiator (D) and having a carboxyl group - containing a compound having a carbon double bond (F), the ratio of the zwitterionic compound on the conductive filler (a) (B) is 0.05 to 5 wt% der Rushirubeden paste.
(2) The conductive paste according to (1) , wherein the compound (E) having a carboxyl group is an acrylic copolymer containing epoxy acrylate or epoxy methacrylate as an acrylic monomer having a carbon-carbon double bond.
( 3 ) The zwitterionic compound (B) is a compound selected from the group consisting of an amino acid, a compound represented by the following general formula (1) and a compound represented by the following general formula (2). ) Or (2) .

(Wherein R ¹ , R ² and R ³ each independently represents an organic group, L ¹ represents a divalent linking group. R ³ and R ² or L ¹ are linked to each other to form a ring. And the ring may have a substituent.)

(In the formula, R ⁴ represents an alkyl group having 1 to 6 carbon atoms or hydrogen bonded to any one of positions 1 to 6 of the pyridinium ring, and L ² represents any of positions 1 to 6 of the pyridinium ring. This represents a divalent linking group bonded to one position, and either R ⁴ or L ² is bonded to the 1-position of the pyridinium ring.
(4) The ^R 1, ^{R 2} and ^{R 3} each independently represent an alkyl group having 1 to 6 carbon atoms, (3), wherein the conductive paste.
( 5 ) An application step of applying the conductive paste according to any one of (1) to ( 4 ) on a substrate to obtain a coating film, and a drying step of drying the coating film to obtain a dry film; A method for producing a conductive pattern, comprising: a pattern forming step of exposing and developing the dry film to obtain a pattern; and a curing step of curing the pattern at 100 to 200 ° C. to obtain a conductive pattern.
( 6 ) A capacitive touch panel comprising a conductive pattern manufactured by the conductive pattern manufacturing method according to ( 5 ) as a peripheral wiring.

  According to the conductive paste of the present invention, not only a fine conductive pattern having excellent adhesion can be obtained, but also a conductive pattern having a low specific resistance can be obtained under low temperature curing conditions.

It is a schematic diagram which shows the translucent pattern of the photomask used for the specific resistance evaluation of an Example.

  The conductive paste of the present invention contains a conductive filler (A), a zwitterionic compound (B) and a thermosetting compound (C). Using the conductive paste of the present invention, it is possible to form a conductive pattern constituting an electrode wiring by a method such as a screen printing method or a photosensitive method (photolithography method).

  Examples of the conductive filler (A) contained in the conductive paste of the present invention include Ag, Au, Cu, Pt, Pb, Sn, Ni, Al, W, Mo, ruthenium oxide, Cr, Ti, carbon or indium. Particles. Particles in which these materials are combined can also be used. Mixtures of these particles can also be used. Ag, Cu or Au particles are preferable from the viewpoint of conductivity, and Ag particles are more preferable from the viewpoint of cost and stability.

  The median diameter (D50) of the conductive filler (A) is preferably from 0.1 μm to 10 μm, and more preferably from 0.5 μm to 6 μm. When D50 is 0.1 μm or more, the contact probability between the conductive fillers (A) in the curing step is improved, and the specific resistance and disconnection probability of the manufactured conductive pattern are reduced. Furthermore, in the exposure process, the exposure light can smoothly pass through the coating film obtained by applying the conductive paste, facilitating fine patterning. On the other hand, when D50 is 10 μm or less, the surface smoothness, pattern accuracy, and dimensional accuracy of the manufactured conductive pattern are improved. D50 can be measured by a laser light scattering method.

  The proportion of the conductive filler (A) in the total solid content in the conductive paste is preferably 60% by weight to 95% by weight, more preferably 70% by weight to 90% by weight, based on the total solid content in the conductive paste. . When the addition amount with respect to the total solid content is 60% by weight or more, the contact probability between the conductive fillers (A) in the curing process is improved, and the specific resistance and the disconnection probability of the manufactured conductive pattern are lowered. On the other hand, if the addition amount with respect to the total solid content is 95% by weight or less, the exposure light can smoothly pass through the coating film obtained by applying the conductive paste in the exposure step, and fine patterning is easy. Become. Here, the total solid content means all components of the conductive paste excluding the solvent.

  The proportion of the conductive filler (A) in the total solid content of the conductive paste is determined by adding organic components such as the conductive filler (A), zwitterionic compound (B) and thermosetting compound (C) at the time of preparing the conductive paste. Can be controlled by quantity. The proportion of the conductive filler (A) in the total solid content can be measured by thermogravimetry (hereinafter, “TGA”). More specifically, a weight change of 25 to 600 ° C. can be measured by TGA (for example, TGA-50; manufactured by Shimadzu Corporation) using about 10 mg of conductive paste as a sample. Usually, since the solvent in the conductive paste evaporates at 100 to 150 ° C., the sample weight when reaching 150 ° C. corresponds to the weight of the total solid content. The sample weight at the time of reaching 600 ° C. is substantially equivalent to the weight of the conductive filler (A) from which the zwitterionic compound (B) and the thermosetting compound (C) are removed. Therefore, the ratio of the conductive filler (A) in the total solid content is determined from the ratio of the sample weight when reaching 600 ° C. to the sample weight when reaching 150 ° C. Moreover, when using a conductive pattern as a sample, it can measure by TGA similarly to a paste by scraping and collecting a conductive pattern.

  The zwitterionic compound (B) (hereinafter referred to as “compound (B)”) contained in the conductive paste of the present invention refers to a compound having both a positive charge and a negative charge in one molecule. Although the detailed mechanism is unknown, by containing the compound (B), a conductive pattern having a low specific resistance can be obtained even under low temperature curing conditions.

  Examples of the compound (B) include carnitine, acetylcarnitine, N, N, N-trimethylglycine (also known as glycine betaine), N, N, N-triethylglycine, N, N, N-tripropylglycine, N, N, N-triisopropylglycine, N, N, N-trimethyl-γ-aminobutyric acid, N, N, N-trimethylalanine, N, N, N-triethylalanine, N, N, N-triisopropylalanine, N , N, N-trimethyl-2-methylalanine, N, N, N-trimethylammoniopropionate or low molecular betaine having a carboxylate anion such as proline betaine.

  Also, lauryl betaine (for example, Amphithol 24B (active ingredient 26 wt%; manufactured by Kao Corporation)), stearyl betaine, lauric acid amidopropyl betaine, coconut oil fatty acid amidopropyl betaine, octanoic acid amidopropyl betaine or 2-alkyl- An amphoteric surfactant having a quaternary ammonium cation and a carboxylate anion such as N-carboxymethyl-N-hydroxyethylimidazolinium betaine (for example, Amphital 20YB (active ingredient 40% by weight; manufactured by Kao Corporation)) Can be mentioned.

  Moreover, Yukaformer (registered trademark) AMPHOSET, Yukaformer (registered trademark) 104D, Yukaformer (registered trademark) 301 or Yukaformer (registered trademark) SM (all of which are manufactured by Mitsubishi Chemical Corporation), RAM Resin-1000, RAM Resin-2000 And polymers having a quaternary ammonium cation and a carboxylate anion in the side chain, such as RAM Resin-3000 or RAM Resin-4000 (all of which are Osaka Organic Chemical Industries, Ltd.).

  Moreover, the compound which has pyridinium cations and carboxylate anions, such as pyridinoacetate, pyridinopropionate, or trigonelin, is mentioned.

  Further, octadecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt, dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt, stearylsulfobetaine, palmitylsulfobetaine, myristylsulfobetaine, laurylsulfobetaine, coca Examples thereof include compounds having a quaternary ammonium cation and a sulfonate anion such as midpropylhydroxysultain, 3- (ethyldimethylammonio) propane-1-sulfonate or 3- (benzyldimethylammonio) propane-1-sulfonate.

  Moreover, the compound which has pyridinium cations, such as 1- (3-sulfopropyl) pyridinium hydroxide internal salt, and a sulfonate anion is mentioned.

  Moreover, the compound which has quaternary ammonium cations, such as phosphatidylcholine or a lecithin, and a phosphate anion is mentioned.

  Moreover, amine oxide type compounds, such as a lauryl dimethylamine N-oxide, an oleyl dimethylamine N-oxide, a nicotinic acid N-oxide, 2-methylpyridine N-oxide, a trimethylamine N-oxide, or a pyridine N-oxide, are mentioned.

  Alternatively, alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, N-methylglycine, β- Examples include amino acids such as alanine, ornithine, creatine, γ-aminobutyric acid, theanine or kainic acid.

  As the compound (B), an amino acid or a compound having a structure represented by the following general formula (1) or (2) is preferable.

(Wherein R ¹ , R ² and R ³ each independently represents an organic group, L ¹ represents a divalent linking group. R ³ and R ² or L ¹ are linked to each other to form a ring. And the ring may have a substituent.)

(In the formula, R ⁴ represents an alkyl group having 1 to 6 carbon atoms or hydrogen bonded to any one of positions 1 to 6 of the pyridinium ring, and L ² represents any of positions 1 to 6 of the pyridinium ring. This represents a divalent linking group bonded to one position, and either R ⁴ or L ² is bonded to the 1-position of the pyridinium ring.
R ¹ , R ² and R ³ are preferably each independently an alkyl group having 1 to 6 carbon atoms. Examples of the compound having the structure of the general formula (1) or (2), wherein R ¹ , R ² and R ³ are alkyl groups having 1 to 6 carbon atoms include carnitine, acetyl carnitine, N, N, N-trimethylglycine, N, N, N-triethylglycine, N, N, N-tripropylglycine, N, N, N-triisopropylglycine, N, N, N-trimethyl-γ-aminobutyric acid, N, N , N-trimethylalanine, N, N, N-triethylalanine, N, N, N-triisopropylalanine, N, N, N-trimethyl-2-methylalanine or N, N, N-trimethylammoniopropionate Can be mentioned. Carnitine or N, N, N-trimethylglycine is more preferred.

  Examples of the divalent linking group include a hydrocarbon group such as an alkylene group, an alkenylene group, an alkynylene group or an arylene group, an aromatic heterocyclic ring such as a thiophene-2,5-diyl group or a pyrazine-2,3-diyl group. A divalent linking group derived from a compound having a heterocycle (heteroaromatic compound), a divalent linking group derived from a chalcogen atom such as O or S, or a hetero such as an alkylimino group, a dialkylsilanediyl group or a diarylgermandiyl group And a group linked through an atom. The alkylene group may have a substituent such as a hydroxyl group or an alkyl group. The alkylene group is preferably a methylene group, an ethylene group, a trimethylene group or a tetramethylene group.

  The ratio of the compound (B) to the conductive filler (A) is preferably from 0.05% by weight to 5% by weight, and more preferably from 0.1% by weight to 2% by weight. When the ratio of the compound (B) is 0.05% by weight or more, a conductive pattern having a low specific resistance can be obtained under low temperature curing conditions. On the other hand, when the proportion of the compound (B) is 5% by weight or less, the development resistance at the time of patterning is sufficient, and a fine pattern can be formed.

  The ratio of the compound (B) to the conductive filler (A) can be calculated by quantitatively analyzing the contents of the conductive filler (A) and the compound (B) in the paste by the total component analysis of the conductive paste.

The method for analyzing all components of the conductive paste is as follows.
(I) The conductive paste is diluted with an organic solvent, and ¹ H-NMR measurement, GC measurement, and GC / MS measurement are performed to examine its outline.
(Ii) The conductive paste is extracted with an organic solvent and then centrifuged to separate soluble and insoluble components.
(Iii) The insoluble matter is extracted with a highly polar organic solvent and then centrifuged to further separate the soluble and insoluble matters.
(Iv) IR measurement, ¹ H-NMR measurement, and GC / MS measurement are performed on the mixture of soluble components obtained in (ii) and (iii) above. Further, the above mixed solution is collected by GPC. The obtained fraction is subjected to IR measurement and ¹ H-NMR measurement. Moreover, about this fraction, GC measurement, GC / MS measurement, pyrolysis GC / MS measurement, and MALDI / MS measurement are performed as needed.
(V) Perform IR measurement or TOF-SIMS measurement on the insoluble matter obtained in (iii) above. When it is confirmed that organic substances are present, pyrolysis GC / MS or TPD / MS measurement is performed.
(Vi) By comprehensively judging the measurement results of (i), (iv) and (v) above, the content of each component contained in the conductive paste can be determined. In addition, as a highly polar organic solvent used by said (iii), chloroform or methanol is preferable.

  The compound (B) may be contained in the conductive paste in a state of covering the conductive filler (A). As a surface treatment method for coating the conductive filler (A) with the compound (B), a known method such as a wet treatment or a dry treatment can be used.

  The thermosetting compound (C) (hereinafter referred to as “compound (C)”) contained in the conductive paste of the present invention can enhance the adhesion of the conductive paste to the substrate or the coating film. As a thermosetting compound (C), an epoxy compound, an oxetane compound, an isocyanate compound, or an alkoxy compound is mentioned, for example.

  Examples of the epoxy compound include bisphenol A type, hydrogenated bisphenol A type, bisphenol F type, bisphenol S type, phenol novolak type, cresol novolak type, bisphenol A novolak type, biphenol type, bixylenol type, trisphenol methane type, Examples include glycidylamine type or glycidyl ester type epoxy resins or phenoxy resins.

  Further, α-triglycidyl isocyanurate, β-triglycidyl isocyanurate, alicyclic epoxy resin, alicyclic phenoxy resin, heterocyclic epoxy resin, or heterocyclic phenoxy resin can be given.

  Examples of the epoxy compound include jER (registered trademark) 828, Adeka Resin EPR-21, Adeka Resin EPR-4030, jER (registered trademark) 1001, jER (registered trademark) 1002, or jER (registered trademark) 1256.

  The epoxy equivalent of the epoxy compound is preferably 200 to 500 g / equivalent. By setting the epoxy equivalent to 200 to 500 g / equivalent, a conductive pattern having high adhesion to various substrates such as a resin film and a glass substrate can be obtained. The epoxy equivalent means the weight of a resin containing 1 equivalent of an epoxy group, and can be obtained by dividing the molecular weight obtained from the structural formula by the number of epoxy groups contained in the structure.

  Examples of the oxetane compound include 3-ethyl-3-hydroxymethyloxetane (for example, Aron oxetane (registered trademark) OXT-101; manufactured by Toagosei Co., Ltd.), 2-ethylhexyloxetane, xylylenebisoxetane, 3-ethyl. -{[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 1,4 -Bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, bis (3-ethyl-3-oxetanylmethyl) ether or phenol novolac type oxetane compounds.

  Examples of the isocyanate compound include phenylene diisocyanate, toluylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate, trimethylphenylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate. Isophorone diisocyanate is preferred because the reaction can be easily controlled. Moreover, you may use the blocked isocyanate compound by which the isocyanate group was blocked with the amine.

  An alkoxy compound refers to a compound having in its molecule an alkoxy group that condenses by heating to produce an alcohol. As an alkoxy group, a methoxy group, an ethoxy group, a butoxy group, or an isobutoxy group is mentioned, for example. Examples of the alkoxy compound include N-methoxymethyl acrylamide, N-ethoxymethyl acrylamide, Nn-butoxymethyl acrylamide, N-isobutoxymethyl acrylamide, butoxyethyl acrylate, butoxytriethylene glycol acrylate, HMOM-TPHAP (Honshu Chemical) Manufactured by Kogyo Co., Ltd.), MW-30M, MW-30, MW-22, MS-11, MS-001, MX-730, MX-750, MX-706, MX-035, BL-60, BX-37, MX -302, MX-45, MX-410, BX-4000, or BX-37 (all of which are manufactured by Sanwa Chemical Co., Ltd.) or Nicarak (registered trademark) MW-30HM, Nicarak (registered trademark) MW-390, Nicarac (registered) Trademark) MX-270, Nikarak ( Recording trademark) MX-280, NIKALACK (registered trade mark) MW-100LM or NIKALACK (registered trademark) any MX-750LM (more Sanwa Chemical Co., Ltd.) and the like.

  It is preferable that the electrically conductive paste of this invention contains a photoinitiator (D) as needed. Here, the photopolymerization initiator (D) refers to a compound that decomposes by absorbing light having a short wavelength such as ultraviolet rays or generates a radical by causing a hydrogen abstraction reaction. Examples of the photopolymerization initiator (D) include 2- (benzoyloxyimino) -1- [4- (phenylthio) phenyl] -1-octanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2 , 4,6-trimethylbenzoyl) phenylphosphine oxide, 6- [1- (acetyloxyimino) ethyl] -9-ethyl-9H-carbazol-3-yl (2-methylphenyl) ketone, benzophenone, o-benzoylbenzoate Acid methyl, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, 4,4′-dichlorobenzophenone, 4-benzoyl-4′-methyldiphenyl ketone, dibenzyl ketone, fluorenone 2,2'-diethoxyacetophenone, 2,2 Dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, pt-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, benzyl, benzyldimethyl Ketal, benzyl-β-methoxyethyl acetal, benzoin, benzoin methyl ether, benzoin butyl ether, anthraquinone, 2-t-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone, anthrone, benzanthrone, dibenzosuberone, methyleneanthrone, 4-azidobenzalacetophenone, 2,6-bis (p-azidobenzylidene) cyclohexanone, 6-bis (p-azidoben) Ridene) -4-methylcyclohexanone, 1-phenyl-1,2-butanedione-2- (o-methoxycarbonyl) oxime, 1-phenyl-propanedione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-propane Dione-2- (o-benzoyl) oxime, 1,3-diphenyl-propanetrione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxy-propanetrione-2- (o-benzoyl) oxime, Michler's ketone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone, naphthalenesulfonyl chloride, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone (for example , IRGACURE (registered trademark) 369), quinoline Honyl chloride, N-phenylthioacridone, 4,4′-azobisisobutyronitrile, diphenyl disulfide, benzthiazole disulfide, triphenylphosphine, camphorquinone, 2,4-diethylthioxanthone, isopropylthioxanthone, tetrabromide Examples include carbon, tribromophenyl sulfone, benzoin peroxide, eosin, or a combination of a photoreductive dye such as methylene blue and a reducing agent such as ascorbic acid or triethanolamine.

  The addition amount of the photopolymerization initiator (D) is preferably 0.05 parts by weight or more and 100 parts by weight or less, and more preferably 0.5 parts by weight or more and 15 parts by weight or less with respect to 15 parts by weight of the compound (C). When the added amount with respect to 15 parts by weight of the compound (C) is 0.05 parts by weight or more, the cured density of the part exposed to the conductive paste increases, and the residual film ratio after development increases. On the other hand, when the added amount with respect to 15 parts by weight of the compound (C) is 100 parts by weight or less, excessive light absorption at the upper part of the coating film obtained by applying the conductive paste is suppressed. As a result, a decrease in adhesion with the substrate due to the manufactured conductive pattern having an inversely tapered shape is suppressed.

  The electrically conductive paste of this invention may contain the sensitizer with the photoinitiator (D).

  Examples of the sensitizer include 2,4-diethylthioxanthone, isopropylthioxanthone, 2,3-bis (4-diethylaminobenzal) cyclopentanone, 2,6-bis (4-dimethylaminobenzal) cyclohexanone, 2 , 6-bis (4-dimethylaminobenzal) -4-methylcyclohexanone, Michler's ketone, 4,4-bis (diethylamino) benzophenone, 4,4-bis (dimethylamino) chalcone, 4,4-bis (diethylamino) chalcone P-dimethylaminocinnamylidene indanone, p-dimethylaminobenzylidene indanone, 2- (p-dimethylaminophenylvinylene) isonaphthothiazole, 1,3-bis (4-dimethylaminophenylvinylene) isonaphthothiazole, 1,3-bis (4-dimethyl) Minobenzal) acetone, 1,3-carbonylbis (4-diethylaminobenzal) acetone, 3,3-carbonylbis (7-diethylaminocoumarin), N-phenyl-N-ethylethanolamine, N-phenylethanolamine, N- Examples include tolyldiethanolamine, isoamyl dimethylaminobenzoate, isoamyl diethylaminobenzoate, 3-phenyl-5-benzoylthiotetrazole or 1-phenyl-5-ethoxycarbonylthiotetrazole.

  The addition amount of the sensitizer is preferably 0.05 parts by weight or more and 30 parts by weight or less, and more preferably 0.1 parts by weight or more and 8 parts by weight or less with respect to 15 parts by weight of the compound (C). When the addition amount with respect to 15 parts by weight of the compound (C) is 0.05 parts by weight or more, the exposure sensitivity is sufficiently improved. On the other hand, when the addition amount relative to 15 parts by weight of the compound (C) is 30 parts by weight or less, excessive light absorption at the upper part of the coating film obtained by applying the conductive paste is suppressed. As a result, a decrease in adhesion with the substrate due to the manufactured conductive pattern having an inversely tapered shape is suppressed.

  It is preferable that the electrically conductive paste of this invention contains the compound (E) which has a carboxyl group (henceforth "compound E") as needed. Compound (E) refers to a monomer, oligomer or polymer having one or more carboxyl groups.

  As a compound (E), an acrylic copolymer is mentioned, for example. Here, the acrylic copolymer refers to a copolymer containing an acrylic monomer having a carbon-carbon double bond as a copolymer component. When making the electrically conductive paste of this invention photosensitive, since the reaction rate of the hardening reaction by exposure can be enlarged, it is preferable that a compound (E) has a carbon-carbon double bond. By containing a photoinitiator (D) with the compound (E) which has a carbon-carbon double bond, the electrically conductive paste of this invention can be made photosensitive. Here, the photosensitivity means that a reaction such as photocrosslinking, photopolymerization, photodepolymerization, or photomodification occurs by irradiating actinic rays to the coating film after coating and drying, and the chemical structure of the irradiated part Is a property that can be developed with a developing solution.

  Examples of the acrylic monomer having a carbon-carbon double bond include methyl acrylate, acrylic acid, 2-ethylhexyl acrylate, ethyl acrylate, n-butyl acrylate, iso-butyl acrylate, iso-propane acrylate, glycidyl acrylate, N- Methoxymethylacrylamide, N-ethoxymethylacrylamide, Nn-butoxymethylacrylamide, N-isobutoxymethylacrylamide, butoxytriethylene glycol acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, 2-hydroxyethyl acrylate, isobonyl Acrylate, 2-hydroxypropyl acrylate, isodexyl acrylate, isooctyl acrylate, lauryl acrylate , 2-methoxyethyl acrylate, methoxyethylene glycol acrylate, methoxydiethylene glycol acrylate, octafluoropentyl acrylate, phenoxyethyl acrylate, stearyl acrylate, trifluoroethyl acrylate, acrylamide, aminoethyl acrylate, phenyl acrylate, phenoxyethyl acrylate, 1-naphthyl acrylate 2-naphthyl acrylate, thiophenol acrylate, benzyl mercaptan acrylate, allylated cyclohexyl diacrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol Diac Relay , Polyethylene glycol diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, ditrimethylolpropane tetraacrylate, glycerol diacrylate, methoxylated cyclohexyl diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, polypropylene glycol di Acrylic monomers such as acrylate, triglycerol diacrylate or trimethylolpropane triacrylate can be mentioned.

  In addition, an acrylic acid adduct of ethylene glycol diglycidyl ether, an acrylic acid adduct of diethylene glycol diglycidyl ether, an acrylic acid adduct of neopentyl glycol diglycidyl ether, which has a hydroxyl group obtained by opening an epoxy group with an unsaturated acid, Epoxy acrylates such as acrylic acid adducts of glycerin diglycidyl ether, acrylic acid adducts of bisphenol A type epoxy resins, acrylic acid adducts of bisphenol F type epoxy resins or acrylic acid adducts of cresol novolac type epoxy resins are also acrylic. Listed as a monomer.

  Examples of the compound (E) include a methacrylic copolymer. Here, the methacrylic copolymer refers to a copolymer containing a methacrylic monomer having a carbon-carbon double bond as a copolymerization component. Examples of the methacrylic monomer include compounds in which the acrylic group of the acrylic monomer is substituted with a methacrylic group. Hereinafter, it may be called an acrylic copolymer including a methacrylic copolymer.

  An acrylic copolymer containing epoxy acrylate or epoxy methacrylate as an acrylic monomer having a carbon-carbon double bond is preferred to form a conductive pattern with higher hardness, and an epoxy obtained by adding a polyfunctional isocyanate to a hydroxyl group. An acrylic copolymer containing acrylate or epoxy methacrylate is more preferable.

  The alkali-soluble acrylic copolymer having a carboxyl group can be obtained by using an unsaturated acid such as an unsaturated carboxylic acid as a monomer. Examples of the unsaturated acid include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, and acid anhydrides thereof. The acid value of the obtained acrylic copolymer can be adjusted by the amount of the unsaturated acid used.

  In addition, “an acrylic copolymer containing an epoxy acrylate or an epoxy methacrylate in which a polyfunctional isocyanate is added to a hydroxyl group” having a carboxyl group is an epoxy acrylate or an epoxy methacrylate, and a polyhydric alcohol having a polyfunctional isocyanate and a carboxyl group. Can be obtained by reacting

  Moreover, it has a reactive unsaturated double bond in the side chain by reacting the carboxyl group of the acrylic copolymer with a compound having an unsaturated double bond such as glycidyl (meth) acrylate. An alkali-soluble acrylic copolymer is obtained.

  Examples of other copolymer components contained in the acrylic copolymer include styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, α-methylstyrene, chloromethylstyrene, and hydroxymethylstyrene. Examples include styrenes, γ-methacryloxypropyltrimethoxysilane, and 1-vinyl-2-pyrrolidone.

  The acid value of the compound (E) is preferably 40 to 250 mgKOH / g and more preferably 50 to 200 mgKOH / g in order to optimize the alkali solubility of the compound (E). When the acid value is 40 mgKOH / g or more, the solubility of the soluble part becomes good. On the other hand, when the acid value is 250 mgKOH / g or less, the development tolerance is widened. In addition, the acid value of a compound (E) can be measured based on JISK0070 (1992).

  The addition amount of the compound (E) is preferably 5 parts by weight or more and 150 parts by weight or less, and more preferably 15 parts by weight or more and 80 parts by weight or less with respect to 15 parts by weight of the compound (C). If the amount added to 15 parts by weight of the compound (C) is 5 parts by weight or more, the developability is improved. On the other hand, when the addition amount with respect to 15 parts by weight of the compound (C) is 150 parts by weight or less, the content of the compound (C) is relatively increased, and the adhesion is improved.

  It is preferable that the electrically conductive paste of this invention contains the compound (F) (henceforth "compound F") which has a carbon-carbon double bond as needed. By containing a photoinitiator (D) and a compound (F), the electrically conductive paste of this invention can be made photocurable. Moreover, the electroconductive paste of this invention can be provided with photosensitivity by containing a photoinitiator (D), a compound (E), and a compound (F). In addition, when the said compound (E) also has a carbon-carbon double bond in addition to a carboxyl group, since compound (E) itself has photocurability, it is necessary to contain the compound (F) May decrease. Even if the compound (E) has a carbon-carbon double bond in addition to the carboxyl group, it is not included in the compound (F).

  Examples of the compound (F) include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, allyl acrylate, and benzyl. Acrylate, butoxyethyl acrylate, butoxytriethylene glycol acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, 2-ethylhexyl acrylate, glycerol acrylate, glycidyl acrylate, heptadecafluorodecyl acrylate, 2-hydroxyethyl acrylate, iso Bonyl acrylate, 2-hydroxypropyl acrylate , Isodexyl acrylate, isooctyl acrylate, lauryl acrylate, 2-methoxyethyl acrylate, methoxyethylene glycol acrylate, methoxydiethylene glycol acrylate, octafluoropentyl acrylate, phenoxyethyl acrylate, stearyl acrylate, trifluoroethyl acrylate, allylated cyclohexyldi Acrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol mono Hydroxypentaacryl , Ditrimethylolpropane tetraacrylate, glycerol diacrylate, methoxylated cyclohexyl diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, triglycerol diacrylate, trimethylolpropane triacrylate, acrylamide, aminoethyl Acrylate, phenyl acrylate, phenoxyethyl acrylate, benzyl acrylate, 1-naphthyl acrylate, 2-naphthyl acrylate, bisphenol A diacrylate, diacrylate of bisphenol A-ethylene oxide adduct, diacrylate of bisphenol A-propylene oxide adduct, epoxy Acrylate, urethane acrylate Various acrylic esters such as thiophenol, thiophenol acrylate or benzyl mercaptan acrylate, monomers in which 1 to 5 hydrogen atoms of the aromatic ring of these monomers are substituted with chlorine or bromine atoms, styrene, p-methylstyrene, o- Methylstyrene, m-methylstyrene, chlorinated styrene, brominated styrene, α-methylstyrene, chlorinated α-methylstyrene, brominated α-methylstyrene, chloromethylstyrene, hydroxymethylstyrene, carboxymethylstyrene, vinylnaphthalene Vinyl anthracene or vinyl carbazole.

  Moreover, what substituted a part or all of the acrylate in the molecule | numerator of the compound containing said carbon-carbon double bond by the methacrylate is mentioned. In the polyfunctional monomer, an acrylic group, a methacryl group, a vinyl group, or an allyl group may be mixed. In addition, from the viewpoint of forming a conductive pattern with higher hardness, epoxy acrylate or epoxy methacrylate is preferable.

  The conductive paste of the present invention may contain a solvent. Examples of the solvent include N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, dimethylimidazolidinone, dimethyl sulfoxide, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate (hereinafter “CA”). ), Diethylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, γ-butyrolactone, ethyl lactate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, ethylene glycol mono-n-propyl ether, diacetone Examples include alcohol, tetrahydrofurfuryl alcohol or propylene glycol monomethyl ether acetate.

  The amount of compound (F) added is preferably 0.3 parts by weight or more and 90 parts by weight or more, and more preferably 3 parts by weight or more and 30 parts by weight or less with respect to 15 parts by weight of compound (C). When the addition amount relative to 15 parts by weight of the compound (C) is 0.3 parts by weight or more, the development resistance of the exposed part is improved. On the other hand, when the addition amount with respect to 15 parts by weight of the compound (C) is 90 parts by weight or less, the content of the compound (C) is relatively increased, and the adhesion is improved.

  The conductive paste of the present invention is a non-photosensitive polymer or plasticizer that does not have an unsaturated double bond in the molecule, a leveling agent, a surfactant, a silane coupling agent, as long as the desired properties are not impaired. You may contain additives, such as a hardening | curing agent and hardening accelerator, an antifoamer, or a pigment.

  Examples of the non-photosensitive polymer include cellulose compounds such as methyl cellulose and ethyl cellulose, and high molecular weight polyethers.

  Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, polyethylene glycol, and glycerin.

  Examples of the leveling agent include a special vinyl polymer or a special acrylic polymer.

  Examples of the silane coupling agent include methyltrimethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, hexamethyldisilazane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and vinyltrimethylsilane. Methoxysilane is mentioned.

  Examples of the curing agent / curing accelerator include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole and 4-phenylimidazole, dicyandiamide, and benzyldimethyl. Amines, amine compounds such as 4-methoxy-N, N-dimethylbenzylamine or 4-methyl-N, N-dimethylbenzylamine, hydrazide compounds such as adipic acid dihydrazide or sebacic acid dihydrazide, or phosphorus compounds such as triphenylphosphine Is mentioned.

  The electrically conductive paste of this invention is manufactured using dispersers or kneading machines, such as a three-roller, a ball mill, or a planetary ball mill, for example.

  Next, a method for producing a conductive pattern using the conductive paste of the present invention will be described.

  The conductive pattern obtained by the method for producing a conductive pattern of the present invention is a composite of an organic component and an inorganic component, and the conductive fillers (C) contained in the conductive paste of the present invention are cured during curing. Conductivity is manifested by contact with each other by contraction.

  In order to produce a conductive pattern, first, the conductive paste of the present invention is applied onto a substrate to obtain a coating film, and the obtained coating film is dried to volatilize the solvent. Thereafter, the dried film is exposed through a pattern forming mask and then developed to form a desired pattern on the substrate. And if the obtained pattern is cured at 100 ° C. or more and 200 ° C. or less, a conductive pattern can be obtained. The curing temperature is more preferably 120 ° C. or higher and 150 ° C. or lower. When the curing temperature is less than 100 ° C., the volume shrinkage of the resin does not increase and the specific resistance cannot be lowered. On the other hand, when the heating temperature exceeds 200 ° C., a conductive pattern cannot be formed on a material such as a substrate having low heat resistance. That is, the low temperature curing condition is 200 ° C. or lower.

  Examples of the substrate include a polyethylene terephthalate film (hereinafter referred to as “PET film”), a polyimide film, a polyester film, an aramid film, an epoxy resin substrate, a polyetherimide resin substrate, a polyetherketone resin substrate, a polysulfone resin substrate, and a glass substrate. , A silicon wafer, an alumina substrate, an aluminum nitride substrate, a silicon carbide substrate, a decorative layer forming substrate, or an insulating layer forming substrate.

  Examples of the method for applying the conductive paste of the present invention to a substrate include spin coating using a spinner, spray coating, roll coating, screen printing, or coating using a blade coater, die coater, calendar coater, meniscus coater, or bar coater. Is mentioned. The film thickness of the obtained coating film may be appropriately determined according to the coating method or the total solid content concentration or viscosity of the conductive paste, but the film thickness after drying may be 0.1 μm or more and 50 μm or less. preferable. The film thickness can be measured by using a stylus step meter such as Surfcom (registered trademark) 1400 (manufactured by Tokyo Seimitsu Co., Ltd.). More specifically, the film thickness at three random positions may be measured with a stylus-type step gauge (length measurement: 1 mm, scanning speed: 0.3 mm / sec), and the average value may be defined as the film thickness. it can.

  Examples of the method for drying the obtained coating film to volatilize and remove the solvent include heat drying or vacuum drying using an oven, a hot plate or infrared rays. The heating temperature is preferably 50 ° C. or higher and 150 ° C. or lower, and the heating time is preferably 1 minute to several hours.

  The coating film is exposed after drying. In general, the exposure is performed through a photomask, as in normal photolithography. Further, a method of directly drawing with a laser beam or the like without using a photomask may be used. Examples of the exposure apparatus include a stepper exposure machine or a proximity exposure machine. Examples of the active light source used at this time include near-ultraviolet rays, ultraviolet rays, electron beams, X-rays, and laser light, and ultraviolet rays are preferable. Examples of the ultraviolet light source include a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a halogen lamp, and a germicidal lamp, and an ultra-high pressure mercury lamp is preferable.

  A desired pattern is obtained by developing the exposed dry film using a developer and dissolving and removing unexposed portions. Examples of the developer used for alkali development include tetramethylammonium hydroxide, diethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, diethylamine, methylamine, dimethylamine, and dimethyl acetate. An aqueous solution of aminoethyl, dimethylaminoethanol, dimethylaminoethyl methacrylate, cyclohexylamine, ethylenediamine or hexamethylenediamine may be mentioned. In these aqueous solutions, polar solvents such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide or γ-butyrolactone, alcohols such as methanol, ethanol or isopropanol, ethyl lactate Alternatively, esters such as propylene glycol monomethyl ether acetate, ketones such as cyclopentanone, cyclohexanone, isobutyl ketone or methyl isobutyl ketone, or a surfactant may be added.

  Examples of the developer for organic development include N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide or hexamethylphosphoryl Examples thereof include polar solvents such as amides or mixed solutions of these polar solvents and methanol, ethanol, isopropyl alcohol, xylene, water, methyl carbitol, or ethyl carbitol.

  As a development method, for example, a method of spraying a developer onto the coating film surface while the substrate is left standing or rotating, a method of immersing the substrate in the developer, or an ultrasonic wave while immersing the substrate in the developer The method of applying is mentioned.

  The pattern obtained by development may be rinsed with a rinse solution. Examples of the rinsing liquid include water or an aqueous solution in which an alcohol such as ethanol or isopropyl alcohol or an ester such as ethyl lactate or propylene glycol monomethyl ether acetate is added to water.

  Examples of the method for curing the obtained pattern include heating with an oven, an inert oven, a hot plate, or the like, heating with infrared rays or microwaves, or heating with xenon flash lamp irradiation.

  The conductive pattern manufactured using the conductive paste of the present invention is suitably used as a peripheral wiring for a touch panel. Examples of the touch panel method include a resistive film type, an optical type, an electromagnetic induction type, and a capacitance type. Since the capacitance type touch panel particularly requires fine wiring, the conductive paste of the present invention is used. The conductive pattern manufactured in this way is more preferably used. In a touch panel provided with a conductive pattern manufactured using the conductive paste of the present invention as its peripheral wiring, and preferably the peripheral wiring is 50 μm pitch (wiring width + inter-wiring width) or less, the frame width can be reduced. The area can be widened.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in more detail, this invention is not limited to these.

  The evaluation methods used in each example and comparative example are as follows.

<Patternability evaluation method>
[Coating process]
The conductive paste was applied on the PET film substrate so that the dry film thickness was 7 μm.

[Drying process]
The obtained coating film was dried in a hot air oven at 100 ° C. for 5 minutes.

[Pattern formation process]
A group of straight lines arranged at a constant line width / interval (hereinafter referred to as “L / S”), that is, a translucent pattern, is taken as one unit, and through a photomask each having nine types of units having different L / S values. The dried film was exposed and developed to obtain 9 types of patterns with different L / S values.

[Cure process]
Thereafter, all of the nine patterns obtained were cured in a hot air oven at 130 ° C. for 60 minutes to obtain nine types of conductive patterns having different L / S values.

The L / S value of each unit included in the photomask is 500/500, 250/250, 100/100, 50/50, 40/40, 30/30, 25/25, 20/20, 15 / 15 (representing each line width (μm) / interval (μm)). The obtained conductive pattern is observed with an optical microscope, a conductive pattern having no residue between the patterns and having no pattern peeling is confirmed, and the L / S value can be developed. The value was / S. The exposure was performed using an exposure apparatus (PEM-6M; manufactured by Union Optical Co., Ltd.) with an exposure amount of 150 mJ / cm ² (wavelength 365 nm conversion), and development was performed with a 0.2 wt% Na ₂ CO ₃ aqueous solution. The substrate was immersed for 30 seconds, and then rinsed with ultrapure water.

<Evaluation method of specific resistance>
The conductive paste was applied onto a PET film so that the dry film thickness was 7 μm, and the obtained coated film was dried in a hot air oven at 100 ° C. for 5 minutes. The dried coating film was exposed and developed through a photomask having a light-transmitting portion A having the pattern shown in FIG. 1 to obtain a pattern. Thereafter, the obtained pattern was cured in a hot air oven at 130 ° C. for 60 minutes to obtain a conductive pattern for specific resistance measurement. The line width of the obtained conductive pattern was 0.400 mm, and the line length was 80 mm.

The exposure and development conditions were the same as in the patterning evaluation method. The resistance value was measured by connecting a resistance meter to each end of the obtained conductive pattern for measuring specific resistance, and the specific resistance was calculated based on the following formula (1).
Specific resistance = resistance value × film thickness × line width / line length (1)
The line width is an average value obtained by observing the line widths at three random positions with an optical microscope and analyzing the image data.

<Method for evaluating adhesion to ITO>
On the PET film with ITO, ELECRYSTA (registered trademark) V270L-TFS (manufactured by Nitto Denko Corporation), the conductive paste was applied so that the thickness of the dry film was 7 μm, and the resulting coated film was heated with hot air at 100 ° C. After drying in an oven for 5 minutes, the entire surface was exposed and developed. The exposure and development conditions were the same as in the patterning evaluation method. Then, the obtained film was cured in a hot air oven at 130 ° C. for 60 minutes, then cut into a 10 × 10 grid pattern with a width of 1 mm, and a constant temperature and humidity chamber at 85 ° C. and 85% RH. It was put into SH-661 (manufactured by ESPEC Corporation) for 240 hours. Cellophane tape (manufactured by Nichiban Co., Ltd.) was applied to the whole cut-out cut portion of the sample taken out and peeled off, and the number of remaining cells was counted.

<Pencil hardness>
On the PET film, the conductive paste was applied so that the dry film thickness was 7 μm, and the obtained coated film was dried in a hot air oven at 100 ° C. for 5 minutes, and then the entire surface was exposed and developed. . The exposure and development conditions were the same as in the patterning evaluation method. Thereafter, the obtained film was cured in a hot air oven at 130 ° C. for 60 minutes, and then the pencil hardness was measured according to the test method of JIS K5600-5-6. The pencil hardness is 10B, 9B, 8B, 7B, 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, 8H, 9H, 10H. There are 22 stages. Using a pencil hardness tester, the highest hardness at which the coating film was not damaged when a load of 1 kg was applied was displayed. The pencil used was Mitsubishi High Uni (Mitsubishi Pencil Co., Ltd.).

  The materials used in each example and comparative example are as follows.

[Conductive filler (A)]
Ag particles having a D50 (median diameter) of 1 μm (D50 is measured using Microtrac HRA (Model No. 9320-X100; manufactured by Nikkiso Co., Ltd.)).

[Zwitterionic compound (B)]
L-alanine (active ingredient 100% by weight; manufactured by Tokyo Chemical Industry Co., Ltd.)
L-leucine (active ingredient 100% by weight; manufactured by Tokyo Chemical Industry Co., Ltd.)
L-phenylalanine (active ingredient 100% by weight; manufactured by Tokyo Chemical Industry Co., Ltd.)
N, N, N-trimethylglycine (active ingredient 100% by weight; manufactured by Wako Pure Chemical Industries, Ltd.)
L-carnitine (active ingredient 100% by weight; manufactured by Wako Pure Chemical Industries, Ltd.)
Yucaformer (registered trademark) AMPHOSET (active ingredient 50% by weight; manufactured by Mitsubishi Chemical Corporation)
Yuka Former (registered trademark) SM (active ingredient 30% by weight; manufactured by Mitsubishi Chemical Corporation)
Anhitoal 24B (active ingredient 26% by weight; manufactured by Kao Corporation)
Amphital 20YB (active ingredient 40% by weight; manufactured by Kao Corporation).

[Thermosetting compound (C)]
Compound (C-1): jER (registered trademark) 828 (containing an epoxy group, epoxy equivalent 188; manufactured by Mitsubishi Chemical Corporation)
Compound (C-2): Adeka Resin EPR-21 (containing epoxy group, epoxy equivalent 210; manufactured by ADEKA Corporation)
Compound (C-3): Adeka Resin EPR-4030 (containing epoxy group, epoxy equivalent 380; manufactured by ADEKA Corporation)
Compound (C-4): jER (registered trademark) 1001 (containing an epoxy group, epoxy equivalent 475, manufactured by Mitsubishi Chemical Corporation)
Compound (C-5): jER (registered trademark) 1002 (containing an epoxy group, epoxy equivalent 650; manufactured by Mitsubishi Chemical Corporation)
Compound (C-6): jER (registered trademark) 1256 (containing an epoxy group, epoxy equivalent 8000; manufactured by Mitsubishi Chemical Corporation)
Compound (C-7): Aron oxetane (registered trademark) OXT-101 (containing oxetane group, manufactured by Toagosei Co., Ltd.).

[Photoinitiator (D)]
IRGACURE (registered trademark) 369 (manufactured by BASF Corporation).

[Compound having carboxyl group (E)]
(Synthesis Example 1)
In a reaction vessel, 200 g of epoxy ester 3000A (manufactured by Kyoeisha Chemical Co., Ltd .; epoxy acrylate compound having bisphenol A skeleton), 260 g of CA, 0.5 g of 2-methylhydroquinone (thermal polymerization inhibitor) and 125 g of 2 , 2-bis (hydroxymethyl) propionic acid was charged and heated to 45 ° C. using an oil bath. To this, 150 g of hexamethylene diisocyanate was gradually added dropwise so that the reaction temperature did not exceed 50 ° C. After completion of the dropping, the reaction temperature was raised to 80 ° C., and after 6 hours, the reaction solution was analyzed by an infrared absorption spectrum measurement method, and it was confirmed that there was no absorption near 2250 cm ⁻¹ . After adding 22 g of glycidyl methacrylate, 10 g of CA, 0.4 g of 2-methylhydroquinone and 1.5 g of triphenylphosphine (reaction catalyst) to this reaction solution, the temperature was further raised to 95 ° C., and the reaction was performed for 6 hours. And a compound (E-1) having a solid content of 64.9% by weight was obtained. The acid value (solid content) of the obtained compound (E-1) was 87 mgKOH / g, and the weight average molecular weight was 12000.

(Synthesis Example 2)
150 g of CA was charged into a reaction vessel in a nitrogen atmosphere, and the temperature was raised to 80 ° C. using an oil bath. To this was added a mixture of 20 g ethyl acrylate, 40 g 2-ethylhexyl methacrylate, 20 g styrene, 15 g acrylic acid, 0.8 g 2,2′-azobisisobutyronitrile and 10 g CA for 1 hour. It was dripped over. After completion of the dropping, a polymerization reaction was further performed for 6 hours. Thereafter, 1 g of hydroquinone monomethyl ether was added to stop the polymerization reaction. Subsequently, a mixture consisting of 5 g of glycidyl methacrylate, 1 g of triethylbenzylammonium chloride and 10 g of CA was added dropwise over 0.5 hours. After completion of the dropwise addition, an additional reaction was performed for 2 hours. The reaction solution obtained was purified with methanol to remove unreacted impurities, and further vacuum-dried for 24 hours to obtain a carboxyl group-containing compound (E-2). The acid value of the obtained compound (E-2) was 97 mgKOH / g, and the weight average molecular weight was 16000.

[Compound (F) having a carbon-carbon double bond]
Light acrylate BP-4EA (manufactured by Kyoeisha Chemical Co., Ltd.).

[solvent]
Diethylene glycol monoethyl ether acetate (CA: manufactured by Tokyo Chemical Industry Co., Ltd.).

Example 1
In a 100 mL clean bottle, 0.186 g of L-leucine as zwitterionic compound (B), 1.5 g of epoxy compound (C-3) as thermosetting compound (C), and compound (E) having a carboxyl group 7.7 g of compound (E-1) (solid content: 5.0 g, CA: 2.7 g), 0.5 g of IRGACURE (registered trademark) 369 as a photopolymerization initiator (D), and 2.3 g of a solvent as a solvent As a compound (F) having CA and a carbon-carbon double bond, 1.0 g of BP-4EA is added, and a revolving mixer “Awatori Nertaro” (registered trademark) (ARE-310; manufactured by Shinky Corporation) ) To obtain 13.186 g of a resin solution (solid content: 62.1% by weight).

  13.186 g of the obtained resin solution and 46.385 g of Ag particles as a conductive filler (A) were mixed and kneaded using a three roller (EXAKT M-50; manufactured by EXAKT), 59.571 g A conductive paste was obtained.

  Using the obtained conductive paste, the patterning property of the conductive pattern, the specific resistance, the adhesion with ITO, and the pencil hardness were evaluated. The developable L / S value, which is an evaluation index of patterning property, was 15/15, and it was confirmed that favorable pattern processing was performed. The specific resistance of the conductive pattern was 58 μΩcm. The number of remaining cells was 100. The pencil hardness was 2H.

(Examples 2-14 and Examples 17-20 , Reference Examples 1-3 )
Table 3 shows the results of producing conductive pastes having the compositions shown in Tables 1 and 2 by the same method as in Example 1 and performing the same evaluation as in Example 1.

(Example 15)
In a 100 mL clean bottle, 1.5 g of the epoxy compound (C-2) as the thermosetting compound (C) and 7.7 g of the compound (E-1) as the compound (E) having a carboxyl group (solid content: 5. 0 g, CA: 2.7 g), 0.5 g of IRGACURE (registered trademark) 369 as a photopolymerization initiator (D), 2.3 g of CA as a solvent, and a compound (F) having a carbon-carbon double bond 1.0 g of BP-4EA as a mixture, and mixed with a rotation and revolution mixer “Awatori Nertaro” (registered trademark) (ARE-310; manufactured by Shinkey Co., Ltd.), and 13.0 g of a resin solution (solid content 61 0.5% by weight).

  On the other hand, 93.86 g of Ag particles as the conductive filler (A) and 2.8 g of a 10 wt% L-alanine aqueous solution (L-alanine: 0.28 g) as the zwitterionic compound (B) were first added to an electric coffee mill ( MJ-518; Melita Japan Co., Ltd.) and mixed and crushed for 10 seconds. Further, 2.8 g of a 10 wt% L-alanine aqueous solution (L-alanine: 0.28 g) was added, and the mixture was pulverized for 20 seconds. The crushed Ag particles were taken out, dried in vacuum at room temperature for 1 hour, and the solvent was removed to obtain Ag particles surface-treated with L-alanine.

  The obtained 13.0 g resin solution and Ag particles surface-treated with 47.21 g L-alanine were mixed and kneaded using three rollers (EXAKT M-50; manufactured by EXAKT). 21 g of conductive paste was obtained.

  Using the obtained conductive paste, the patterning property of the conductive pattern, the specific resistance, the adhesion with ITO, and the pencil hardness were evaluated. The developable L / S value, which is an evaluation index of patterning property, was 15/15, and it was confirmed that favorable pattern processing was performed. The specific resistance of the conductive pattern was 55 μΩcm. The number of remaining cells was 100. The pencil hardness was 2H.

(Example 16)
In a 100 mL clean bottle, put 0.33 g of N, N, N-trimethylglycine as the zwitterionic compound (B), 47.21 g of Ag particles as the conductive filler (A), and 2.3 g of CA as the solvent. The mixture was mixed with a revolutionary mixer “Awatori Nertaro” (registered trademark) (ARE-310; manufactured by Shinkey Co., Ltd.). Thereafter, 1.5 g of the epoxy compound (C-2) as the thermosetting compound (C), 7.7 g of the compound (E-1) as the compound (E) having a carboxyl group (solid content: 5.0 g, CA) 2.7 g), 0.5 g of IRGACURE (registered trademark) 369 as a photopolymerization initiator (D), and 1.0 g of BP-4EA as a compound (F) having a carbon-carbon double bond, This was mixed with a rotation / revolution mixer “Awatori Nertaro” (registered trademark) (ARE-310; manufactured by Shinkey Co., Ltd.). Thereafter, the mixture was kneaded using three rollers (EXAKT M-50; manufactured by EXAKT) to obtain 60.54 g of a conductive paste.

  Using the obtained conductive paste, the patterning property of the conductive pattern, the specific resistance, the adhesion with ITO, and the pencil hardness were evaluated. The developable L / S value, which is an evaluation index of patterning property, was 15/15, and it was confirmed that favorable pattern processing was performed. The specific resistance of the conductive pattern was 49 μΩcm. The number of remaining cells was 100. The pencil hardness was 2H.

(Comparative Examples 1-4)
A conductive paste having the composition shown in Table 2 was produced by the same method as in Example 1, and the results of the same evaluation as in Example 1 are shown in Table 3.

In each of the conductive pastes of Examples 1 to 20 , a conductive pattern excellent in patternability, specific resistance, adhesion with ITO, and hardness could be formed. The conductive pattern formed with the conductive paste of Comparative Example 1 had a high specific resistance. The conductive patterns formed from the conductive pastes of Comparative Examples 2 to 4 had poor adhesion to ITO under high temperature and high humidity. Furthermore, the hardness was insufficient.

A: Translucent part

The electrically conductive paste of this invention can be utilized suitably for manufacture of electrically conductive patterns, such as a surrounding wiring for touchscreens.

Claims (6)

A compound (E) and / or carbon-carbon compound containing a conductive filler (A), a zwitterionic compound (B) , a thermosetting compound (C) and a photopolymerization initiator (D) and having a carboxyl group contains a compound having a double bond (F), the ratio of the zwitterionic compound on the conductive filler (a) (B) is, Ru 0.05-5 wt% der, conductive paste. Compounds having a carboxyl group (E) is carbon - the acrylic monomer having a carbon double bond, epoxy acrylates or epoxy methacrylates are acrylic copolymer containing, according to claim 1, wherein the electrically conductive paste. The zwitterionic compound (B) is an amino acid, is a compound selected from the group consisting of compounds represented by compounds represented by the following general formula (1) and the following general formula (2), according to claim 1 or 2 The electrically conductive paste as described.

(Wherein R ¹ , R ² and R ³ each independently represents an organic group, L ¹ represents a divalent linking group. R ³ and R ² or L ¹ are linked to each other to form a ring. And the ring may have a substituent.)

(In the formula, R ⁴ represents hydrogen having an alkyl group having 1 to 6 carbon atoms bonded to any one of positions 1 to 6 of the pyridinium ring, and L ² represents any of positions 1 to 6 of the pyridinium ring. This represents a divalent linking group bonded to one position, and either R ⁴ or L ² is bonded to the 1-position of the pyridinium ring. Wherein ^R 1, ^{R 2} and ^{R 3} each independently represent an alkyl group having 1 to 6 carbon atoms, according to claim 3, wherein the conductive paste. An application step of applying the conductive paste according to any one of claims 1 to 4 on a substrate to obtain a coating film;
Drying the coating film to obtain a dry film;
A pattern forming step of obtaining a pattern by exposing and developing the dry film; and
And a curing step of curing the pattern at 100 to 200 ° C. to obtain a conductive pattern. A capacitive touch panel comprising the conductive pattern manufactured by the method for manufacturing a conductive pattern according to claim 5 as a peripheral wiring.

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